Regeneration systems for hydrochloric waste pickling solutions

www.andritz.com The leading regeneration technology for hydrochloric waste pickling acid

The ANDRITZ spray roasting and fluid bed pro- When steel is pickled with hydrochloric acid, an iron chloride solu- cesses recycle hydrochloric acid with an efficiency tion is produced: of 99.5% for reuse in your pickling line.

FeO + 2HCl = FeCl2 + H2O

In the regeneration system, the iron chloride (FeCl2) is converted The process into hydrochloric acid and iron oxide by hydrolytic decomposition. The dissolved iron is extracted either as iron oxide powder (spray roasting technology) or as sintered iron oxide (fluidized bed 2 FeCl2 + 2H2O + ½O2 = Fe2O3 + 4HCl technology). This reaction takes place in the reactor at temperatures ranging from 600° C to 800° C. Spray roasting is also used to produce other metal oxides from chloride solutions, for example aluminium, cobalt, magnesium, The iron chloride containing waste pickling acid from the pickling nickel and titanium oxides, rare earth, and various mixed oxides. system is conveyed to the evaporator, where it comes into direct contact with the hot waste gases from the reactor and is concen- trated. This concentrated iron chloride solution is sprayed into the spray roasting reactor or fed to the bed of a fluidized bed reactor.

▲ Advanced 3D design and modelling tools Our technologies provide high saving

At reaction temperatures between 600° C and 800° C the iron The resulting hydrochloric acid (18% by weight) is recycled to the chloride solution is split into hydrogen chloride and iron oxide by pickling process. The gas from the column is cleaned in a scrubber means of water vapor and atmospheric oxygen. stage in accordance with anti-pollution requirements and then dis- charged to the atmosphere. A fan keeps the system under vacuum, After passing through the cyclone, the hydrogen chloride gas, preventing the HCl gas from escaping. w a t e r v a p o r a n d c o m b u s t i o n g a s e s e n t e r t h e e v a p o r a t o r a n d the absorption column, where the HCl gas is absorbed adiabati- Iron oxide powder or sintered iron oxide in the reactor is trans- cally by assign rinse water from the pickling plant. ported to the appropriate tanks and then filled into big bags.

▲ Tank farm ▲ Reactor, venturi, absorbion column

Low acid consumption Acid consumption in pickling plants is substantially reduced when The following are guideline values for a pickling plant for low-carbon a regeneration system is used. strip, based on 32 percent by weight of hydrochloric acid:

Acid consumption with regeneration system: Acid consumption without regeneration system: 0.5-1 kg/t material to be pickled 18-30 kg/t material to be pickled

Heat consumption for spray-roasting and fluidized bed reactors as a function of the iron content in the waste pickling acid from the regeneration system:

Fe content in Spray roasting reactor Fluidized bed reactor

waste pickling acid g/l kJ/kg iron oxide (Fe2O3) kJ/kg iron oxide (Fe2O3) 80 25,000 25,000

100 22,000 23,000

120 18,000 21,000

140 16,000 21,000 Production of high-value iron oxide

Additional revenue from production of high- We ensure a cleaner environment. value iron oxide.

On account of its specific qualities, the iron oxide produced with As the acid loop between the pickling plant and the regeneration the ANDRITZ spray roasting process is highly valued as raw system is closed, and the rinse water from the pickling plant is material and is generating increasing worldwide demand. reused in the regeneration system, the pickling system can be op- erated largely without producing waste water. In order to further increase the value of the iron oxide, a waste acid purification process (WAPUR) was developed. It can reduce the The off-gases from the HCl regeneration system consist of water amount of certain impurities like silicon to a very low value. vapor and the combustion gases from reactor heating. The HCl and dust emission values conform to legal requirements.

Major iron oxide uses Production of hard and soft ferrites Foundry applications Binder materials for refractories Coloring pigments

▲ Oxide conveying system ▲ Regeneration plant Make our experience your advantage Our strengths Recycling of hydrochloric acid with an efficiency of 99.5 % Closed acid loop between the pickling plant and the re- generation system Waste pickle liquors containing Si, Zn, and Pb can be treated Rinse water can be used as absorption water in the regener- ation plant; thus, the pickling plant can be operated without waste water Consistently high pickling quality due to constant iron and acid concentrations Reactors can be heated with any gaseous or liquid fuels High-purity iron oxide as by-product Appropriate E&A models — standard software package providing simulation mode for plant testing and optimization

▲ Reactor base ▲ Dust separator and injection of waste pickle at the evaporator Proven and sophisticated design with more than 200 references worldwide Extract from our reference list

Customer Country Year Capacity l/h

Anyang Iron & Steel China 2011 11,000 Guangxi Liuzhou Iron & Steel China 2010 11,000 Usinas Siderúrgicas de Minas Gerais Brazil 2009 6,000 Acciaieria Arvedi Italy 2009 10,000 Guangzhou JFE Steel Shreet China 2008 9,500 Tian Tie Group China 2006 11,700 Baosteel Shanghai No. 1 China 2006 9,500 Al Ghurair Steel U.A.E. 2006 2,700 Novolipetsk Steel Russia 2005 2,700 voestalpine Stahl Austria 2005 5,000 Benxi Iron & Steel China 2003 12,500 Handan Iron & Steel Group China 2002 8,000 Baoshan Iron & Steel Corp. China 2001 6,000 Inpromesa F. Sidmed S.A. Spain 1999 9,000 voest alpine Stahl Austria 1996 10,000

Choose us as partners steel, stainless steel, and non-ferrous metal the production of steel strip (mechanical, ANDRITZ METALS designs and builds strip. ANDRITZ METALS is one of the few process, and electrical equipment, auto- complete lines for the production and suppliers worldwide capable of providing mation, and life cycle services). further processing of cold-rolled carbon all technologies and processes involved in

Andritz AG Eibesbrunnergasse 20 1120 Vienna, Austria Phone: +43 50805 0 [email protected] www.andritz.com

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